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Insects, Volume 12, Issue 4 (April 2021) – 99 articles

Cover Story (view full-size image): The European Map Butterfly, Araschnia levana, is a favorite model to study the molecular basis and evolutionary ecology of seasonal polyphenism because the daylight length perceived by the caterpillars decides whether the larvae are committed to diapause and overwintering as pupae, resulting in the orange spring phenotype, or whether they entail direct development, resulting in the blackish summer phenotype. Here, we discuss how A. levana butterflies generate different phenotypes from the same genotype under different environmental conditions, which modulate hormonal regulation and transcriptional reprogramming involving control by microRNAs. This polyphenism can be expanded beyond distinct morphological phenotypes to include differences in biomechanical design and immunocompetence. View this paper.
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13 pages, 2215 KiB  
Article
Nectar Uptake of a Long-Proboscid Prosoeca Fly (Nemestrinidae)—Proboscis Morphology and Flower Shape
by Harald W. Krenn, Florian Karolyi, Peter Lampert, Annalie Melin and Jonathan F. Colville
Insects 2021, 12(4), 371; https://doi.org/10.3390/insects12040371 - 20 Apr 2021
Cited by 3 | Viewed by 2895
Abstract
Several Prosoeca (Nemestinidae) species use a greatly elongated proboscis to drink nectar from long-tubed flowers. We studied morphological adaptations for nectar uptake of Prosoecamarinusi that were endemic to the Northern Cape of South Africa. Our study site was a small isolated area [...] Read more.
Several Prosoeca (Nemestinidae) species use a greatly elongated proboscis to drink nectar from long-tubed flowers. We studied morphological adaptations for nectar uptake of Prosoecamarinusi that were endemic to the Northern Cape of South Africa. Our study site was a small isolated area of semi-natural habitat, where the long-tubed flowers of Babiana vanzijliae (Iridaceae) were the only nectar source of P. marinusi, and these flies were the only insects with matching proboscis. On average, the proboscis measured 32.63 ± 2.93 mm in length and less than 0.5 mm in diameter. The short labella at the tip are equipped with pseudotracheae that open at the apical margin, indicating that nectar is extracted out of the floral tube with closed labella. To quantify the available nectar resources, measurements of the nectar volume were taken before the flies were active and after observed flower visits. On average, an individual fly took up approximately 1 µL of nectar per flower visit. The measured nectar quantities and the flower geometry allowed estimations of the nectar heights and predictions of necessary proboscis lengths to access nectar in a range of flower tube lengths. Full article
(This article belongs to the Special Issue Feeding Organs in Hexapoda)
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16 pages, 4940 KiB  
Article
Characterization and Functional Analysis of trehalase Related to Chitin Metabolism in Glyphodes pyloalis Walker (Lepidoptera: Pyralidae)
by Zuo-min Shao, Jian-hao Ding, De-lei Jiang, Zhi-xiang Liu, Yi-jiangcheng Li, Jiao Wang, Jun Wang, Sheng Sheng and Fu-an Wu
Insects 2021, 12(4), 370; https://doi.org/10.3390/insects12040370 - 20 Apr 2021
Cited by 14 | Viewed by 2204
Abstract
Glyphodes pyloalis Walker (G. pyloalis) is a serious pest on mulberry. Due to the increasing pesticide resistance, the development of new and effective environmental methods to control G. pyloalis is needed. Trehalase is an essential enzyme in trehalose hydrolysis and energy [...] Read more.
Glyphodes pyloalis Walker (G. pyloalis) is a serious pest on mulberry. Due to the increasing pesticide resistance, the development of new and effective environmental methods to control G. pyloalis is needed. Trehalase is an essential enzyme in trehalose hydrolysis and energy supply, and it has been considered a promising target for insect pest control. However, the specific function of trehalase in G. pyloalis has not been reported. In this study, two trehalase genes (GpTre1 and GpTre2) were identified from our previous transcriptome database. The functions of the trehalase in chitin metabolism were studied by injecting larvae with dsRNAs and trehalase inhibitor, Validamycin A. The open reading frames (ORFs) of GpTre1 and GpTre2 were 1,704 bp and 1,869 bp, which encoded 567 and 622 amino acid residues, respectively. Both of GpTre1 and GpTre2 were mainly expressed in the head and midgut. The highest expression levels of them were in 5th instar during different development stages. Moreover, knockdown both of GpTre1 and GpTre2 by the dsRNAs led to significantly decreased expression of chitin metabolism pathway-related genes, including GpCHSA, GpCDA1, GpCDA2, GpCHT3a, GpCHT7, GpCHSB, GpCHT-h, GpCHT3b, GpPAGM, and GpUAP, and abnormal phenotypes. Furthermore, the trehalase inhibitor, Validamycin A, treatment increased the expressions of GpTre1 and GpTre2, increased content of trehalose, and decreased the levels of glycogen and glucose. Additionally, the inhibitor caused a significantly increased cumulative mortality of G. pyloalis larvae on the 2nd (16%) to 6th (41.3%) day, and decreased the rate of cumulative pupation (72.3%) compared with the control group (95.6%). After the activities of trehalase were suppressed, the expressions of 6 integument chitin metabolism-related genes decreased significantly at 24 h and increased at 48 h. The expressions of GpCHSB and GpCHT-h, involved in chitin metabolism pathway of peritrophic membrane in the midgut, increased at 24 h and 48 h, and there were no changes to GpCHT3b and GpPAGM. These results reveal that GpTre1 and GpTre2 play an essential role in the growth of G. pyloalis by affecting chitin metabolism, and this provides useful information for insect pest control in the future. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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22 pages, 30119 KiB  
Article
From Phenology and Habitat Preferences to Climate Change: Importance of Citizen Science in Studying Insect Ecology in the Continental Scale with American Red Flat Bark Beetle, Cucujus clavipes, as a Model Species
by Radomir Jaskuła, Marta Kolanowska, Marek Michalski and Axel Schwerk
Insects 2021, 12(4), 369; https://doi.org/10.3390/insects12040369 - 20 Apr 2021
Cited by 11 | Viewed by 5019
Abstract
The American red flat bark beetle, Cucujus clavipes, is a wide distributed saproxylic species divided into two subspecies: ssp. clavipes restricted to eastern regions of North America and ssp. puniceus occurring only in western regions of this continent. Unique morphological features, including [...] Read more.
The American red flat bark beetle, Cucujus clavipes, is a wide distributed saproxylic species divided into two subspecies: ssp. clavipes restricted to eastern regions of North America and ssp. puniceus occurring only in western regions of this continent. Unique morphological features, including body shape and body coloration, make this species easy to recognize even for amateurs. Surprisingly, except some studies focused on physiological adaptations of the species, the ecology of C. clavipes was almost unstudied. Based on over 500 records collected by citizen scientists and deposited in the iNaturalist data base, we studied phenological activity of adult beetles, habitat preferences and impact of future climate change for both subspecies separately. The results clearly show that spp. clavipes and ssp. puniceus can be characterized by differences in phenology and macrohabitat preferences, and their ranges do not overlap at any point. Spp. clavipes is found as more opportunistic taxon occurring in different forests as well as in urban and agricultural areas with tree vegetation always in elevations below 500 m, while elevational distribution of ssp. puniceus covers areas up to 2300 m, and the beetle was observed mainly in forested areas. Moreover, we expect that climate warming will have negative influence on both subspecies with the possible loss of proper niches at level even up to 47–70% of their actual ranges during next few decades. As the species is actually recognized as unthreatened and always co-occurs with many other species, we suggest, because of its expected future habitat loss, to pay more attention to conservationists for possible negative changes in saproxylic insects and/or forest fauna in North America. In addition, as our results clearly show that both subspecies of C. clavipes differ ecologically, which strongly supports earlier significant morphological and physiological differences noted between them, we suggest that their taxonomical status should be verified by molecular data, because very probably they represent separate species. Full article
(This article belongs to the Special Issue The Citizen Science Approach for Expanding the Research on Insects)
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19 pages, 1323 KiB  
Article
Cultural Significance of Beetles in Sub-Saharan Africa
by Arnold van Huis
Insects 2021, 12(4), 368; https://doi.org/10.3390/insects12040368 - 20 Apr 2021
Cited by 5 | Viewed by 7139
Abstract
An overview is given of how beetles are utilised, perceived, and experienced in daily life across sub-Saharan Africa. More than 300 people from 27 countries were interviewed and the results were compared with literature findings. Both the adults and larvae of many beetle [...] Read more.
An overview is given of how beetles are utilised, perceived, and experienced in daily life across sub-Saharan Africa. More than 300 people from 27 countries were interviewed and the results were compared with literature findings. Both the adults and larvae of many beetle species are eaten, mainly from the families Curculionidae, Buprestidae, Cerambycidae, Dytiscidae and Scarabaeidae. Some beetle species are used for medicinal purposes. The use of breast-shaped water beetles by adolescent girls to stimulate breast growth could be due to superstition or the effect of the defensive secretion containing steroid hormones. Blister beetles contain cantharidin, which influences the urinary tract, and is therefore used as an aphrodisiac and for treating venereal disease. Throughout Africa children play with beetles by letting them fly on a string. In the Sahel, the hard work of dung beetles is an inspiration for stories. Fireflies are generally associated with ghosts and witches, likely because the glowing of the beetles is interpreted as magical. Many beetle groups are brightly and attractively coloured and are therefore used in ceremonies and commerce. This type of indigenous knowledge, revealed in stories provided by older people, is rapidly disappearing due to urbanisation. Full article
(This article belongs to the Collection Cultural Entomology: Our Love-hate Relationship with Insects)
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28 pages, 6495 KiB  
Article
Biological Strategies of Invasive Bark Beetles and Borers Species
by Denis A. Demidko, Natalia N. Demidko, Pavel V. Mikhaylov and Svetlana M. Sultson
Insects 2021, 12(4), 367; https://doi.org/10.3390/insects12040367 - 20 Apr 2021
Cited by 5 | Viewed by 3021
Abstract
The present study attempts to identify the biological characteristics of invasive (high-impact in the secondary area) bark beetles and borers species, contributing to their success in an invaded area. We selected 42 species based on the CABI website data on invasive species and [...] Read more.
The present study attempts to identify the biological characteristics of invasive (high-impact in the secondary area) bark beetles and borers species, contributing to their success in an invaded area. We selected 42 species based on the CABI website data on invasive species and information on the most studied regional faunas. Four groups of species with different invasion strategies were identified based on the cluster and factor analysis. The first one (inbred strategy) is characterized by flightless males, xylomycetophagy, low fecundity (~50 eggs), inbreeding, polyvoltinism, and polyphagy. Species with an aggressive strategy are poly- or monovoltine, feeds on a limited number of hosts, larval feeding on the inner bark, are often associated with phytopathogens, and produce aggregation pheromones. Representatives of the polyphagous strategy have a wide range of hosts, high fecundity (~150 eggs), larval feeding on wood, and their life cycle is at least a year long. For the intermediate strategy, the typical life cycle is from a year or less, medium fecundity, feed on inner bark tissues, mono- or oligophagy. Comparison with low-impact alien species showed that the most significant traits from the viewpoint of the potential danger of native plant species are high fecundity, polyvoltinism, presence of symbiotic plant pathogens, long-range or aggregation pheromones. Full article
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6 pages, 6728 KiB  
Communication
Culicoides insignis Lutz, 1913 (Diptera: Ceratopogonidae) Biting Midges in Northeast of Brazil
by Raisa Rodrigues Santos Rios, Maria Clara Alves Santarém, Karlos Antônio Lisboa Ribeiro Júnior, Breno Araujo de Melo, Sybelle Georgia Mesquita da Silva, Neuriane Cavalcante da Silva, Vitória Regina Viana dos Santos, Jakeline Maria dos Santos, Antônio Euzébio Goulart Santana and Angelina Bossi Fraga
Insects 2021, 12(4), 366; https://doi.org/10.3390/insects12040366 - 20 Apr 2021
Cited by 6 | Viewed by 2961
Abstract
The species of the Culicoides genus are hematophagous, and some of them are vectors of important human and animal diseases. This group of insects is distributed worldwide, varying according to local species. Knowledge of the geographic distribution of specific species is crucial for [...] Read more.
The species of the Culicoides genus are hematophagous, and some of them are vectors of important human and animal diseases. This group of insects is distributed worldwide, varying according to local species. Knowledge of the geographic distribution of specific species is crucial for the development and implementation of control strategies. The aim of this work was to investigate the occurrence of Culicoides in the state of Alagoas in northeast Brazil. Midges were captured with CDC light traps, and their identification and morphological analyses were performed by the Ceratopogonidae Collection of the Oswaldo Cruz Foundation (FIOCRUZ/CCER) in Rio de Janeiro, Brazil. Morphological analyses were performed using the key to Culicoides from the guttatus group and comparison with other deposited specimens. DNA sequencing, genetic analysis and comparison with sequences in the Genbank database, confirmed the identification of the flies as Culicoides insignis. This was the first formal report of C. insignis being found in Alagoas. Full article
(This article belongs to the Special Issue Vector-Borne Diseases in a Changing World)
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15 pages, 1078 KiB  
Article
Reproductive Systems, Transfer and Digestion of Spermatophores in Two Asian Luciolinae Fireflies (Coleoptera: Lampyridae)
by Xinhua Fu and Lesley Ballantyne
Insects 2021, 12(4), 365; https://doi.org/10.3390/insects12040365 - 20 Apr 2021
Cited by 2 | Viewed by 3657
Abstract
The internal reproductive anatomy of males and females of two Asian Luciolinae fireflies Emeia pseudosauteri (Geisthardt, 2004) and Abscondita chinensis (L., 1767) is described, and the time course for spermatophore transfer and digestion examined. E. pseudosauteri is sexually dimorphic, with a flightless female, [...] Read more.
The internal reproductive anatomy of males and females of two Asian Luciolinae fireflies Emeia pseudosauteri (Geisthardt, 2004) and Abscondita chinensis (L., 1767) is described, and the time course for spermatophore transfer and digestion examined. E. pseudosauteri is sexually dimorphic, with a flightless female, and Abs. chinensis is sexually monomorphic, with the female flighted. Both are monandrous. Possible female accessory glands are described for the first time for both species. An overview of present knowledge of female reproductive anatomy in the Luciolinae reveals males of 18 species in 10 genera may produce spermatophores and permits speculation about spermatophore production in another 16 genera. Full article
(This article belongs to the Special Issue Reproductive Behaviour in Insects and other Non-Marine Arthropods)
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11 pages, 1313 KiB  
Article
A Peculiar New Genus of Bibionomorpha (Diptera) with Brachycera-Like Modification of Antennae from Mid-Cretaceous Amber of Myanmar
by Jan Ševčík, John Skartveit, Wiesław Krzemiński and Kornelia Skibińska
Insects 2021, 12(4), 364; https://doi.org/10.3390/insects12040364 - 20 Apr 2021
Cited by 7 | Viewed by 2759
Abstract
A new fossil genus of Bibionidae (Diptera: Bibionomorpha), Burmahesperinus gen. nov., from the mid-Cretaceous Burmese amber, is described and illustrated (type species Burmahesperinus antennatus sp. nov., the other two species included are B. conicus sp. nov. and B. pedicellatus sp. nov.). The new [...] Read more.
A new fossil genus of Bibionidae (Diptera: Bibionomorpha), Burmahesperinus gen. nov., from the mid-Cretaceous Burmese amber, is described and illustrated (type species Burmahesperinus antennatus sp. nov., the other two species included are B. conicus sp. nov. and B. pedicellatus sp. nov.). The new genus is tentatively placed in a new subfamily, Burmahesperininae subfam. nov. of the family Bibionidae. Its possible phylogenetic position is briefly discussed. The new genus, as well as the subfamily, possesses the wing venation similar to the recent genus Hesperinus Walker, 1848, in combination with Brachycera-like modification of both the male and female antenna and the overall habitus typical of fungus gnats (Sciaroidea). Full article
(This article belongs to the Special Issue Diptera Diversity in Space and Time)
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3 pages, 182 KiB  
Editorial
Sap-Sucking Pests; They Do Matter
by David Wari, Kazumu Kuramitsu and Nickolas G. Kavallieratos
Insects 2021, 12(4), 363; https://doi.org/10.3390/insects12040363 - 19 Apr 2021
Cited by 3 | Viewed by 2937
Abstract
This is an excerpt giving an overview of the Special Issue: Biology and Management of Sap-Sucking Pests [...] Full article
(This article belongs to the Collection Biology and Management of Sap-Sucking Pests)
11 pages, 3580 KiB  
Article
ERIC and WGS Typing of Paenibacillus larvae in Slovenia: Investigation of ERIC I Outbreaks
by Alenka Žugelj, Bojan Papić, Irena Zdovc, Urška Zajc, Majda Golob, Jana Avberšek and Darja Kušar
Insects 2021, 12(4), 362; https://doi.org/10.3390/insects12040362 - 19 Apr 2021
Cited by 8 | Viewed by 2581
Abstract
Paenibacillus larvae is the causative agent of American foulbrood (AFB), a fatal disease of honeybee brood. Here, we obtained 506 P. larvae isolates originating from honey or brood samples and from different geographic regions of Slovenia in the period 2017–2019. In the first [...] Read more.
Paenibacillus larvae is the causative agent of American foulbrood (AFB), a fatal disease of honeybee brood. Here, we obtained 506 P. larvae isolates originating from honey or brood samples and from different geographic regions of Slovenia in the period 2017–2019. In the first part of the study, we conducted ERIC-PCR typing to assess the frequency of ERIC types in Slovenia. Capillary electrophoresis was used for the analysis of ERIC patterns, revealing good separation efficiency and enabling easy lane-to-lane comparisons. ERIC II was the predominant type (70.2%), followed by ERIC I (29.8%); two slightly altered ERIC I banding patterns were observed but were not considered relevant for the discrimination of ERIC types. No evident spatiotemporal clustering of ERIC types was observed. To assess the clonality of the outbreak-related P. larvae ERIC I isolates, 59 isolates of this type underwent whole-genome sequencing (WGS). Whole-genome multilocus sequence typing (wgMLST) revealed seven ERIC I-ST2 outbreak clusters (≤35 allele differences) with the median intra-outbreak diversity ranging from 7 to 27 allele differences. In all seven clusters, the transmission of P. larvae outbreak clone within a 3-km radius (AFB zone) was observed, which could be explained by the activity of honeybees. In three clusters, the transmission of the outbreak clone between geographically distant apiaries was revealed, which could be explained by the activities of beekeepers such as migratory beekeeping and trading of bee colonies. The present findings reinforce the importance of beekeeping activities in the transmission of P. larvae. WGS should be used as a reference typing method for the detection of P. larvae transmission clusters. Full article
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8 pages, 1820 KiB  
Article
Enhanced Myc Expression in Silkworm Silk Gland Promotes DNA Replication and Silk Production
by Wenliang Qian, Yan Yang, Zheng Li, Yuting Wu, Xuechuan He, Hao Li and Daojun Cheng
Insects 2021, 12(4), 361; https://doi.org/10.3390/insects12040361 - 18 Apr 2021
Cited by 7 | Viewed by 2263
Abstract
Silkworm is an economically important insect that synthetizes silk proteins for silk production in silk gland, and silk gland cells undergo endoreplication during larval period. Transcription factor Myc is essential for cell growth and proliferation. Although silkworm Myc gene has been identified previously, [...] Read more.
Silkworm is an economically important insect that synthetizes silk proteins for silk production in silk gland, and silk gland cells undergo endoreplication during larval period. Transcription factor Myc is essential for cell growth and proliferation. Although silkworm Myc gene has been identified previously, its biological functions in silkworm silk gland are still largely unknown. In this study, we examined whether enhanced Myc expression in silk gland could facilitate cell growth and silk production. Based on a transgenic approach, Myc was driven by the promoter of the fibroin heavy chain (FibH) gene to be successfully overexpressed in posterior silk gland. Enhanced Myc expression in the PSG elevated FibH expression by about 20% compared to the control, and also increased the weight and shell rate of the cocoon shell. Further investigation confirmed that Myc overexpression increased nucleus size and DNA content of the PSG cells by promoting the transcription of the genes involved in DNA replication. Therefore, we conclude that enhanced Myc expression promotes DNA replication and silk protein expression in endoreplicating silk gland cells, which subsequently raises silk yield. Full article
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16 pages, 1350 KiB  
Article
The Effect of Santolina chamaecyparissus and Tagetes patula Essential Oils on Biochemical Markers of Oxidative Stress in Aphids
by Paweł Czerniewicz and Grzegorz Chrzanowski
Insects 2021, 12(4), 360; https://doi.org/10.3390/insects12040360 - 17 Apr 2021
Cited by 9 | Viewed by 1984
Abstract
This study investigated the toxicity of essential oils (EOs) from Santolina chamaecyparissus (L.) and Tagetes patula (L.) towards the green peach aphid Myzus persicae (Sulzer) and the bird cherry-oat aphid Rhopalosiphum padi (L.). The effects of the EOs on aphid population parameters and [...] Read more.
This study investigated the toxicity of essential oils (EOs) from Santolina chamaecyparissus (L.) and Tagetes patula (L.) towards the green peach aphid Myzus persicae (Sulzer) and the bird cherry-oat aphid Rhopalosiphum padi (L.). The effects of the EOs on aphid population parameters and levels of biochemical markers of oxidative stress within insect tissues were analyzed. In laboratory bioassays, application of the studied EOs at sublethal concentrations reduced daily fecundity and led to a decrease in the intrinsic rate of natural increase in both aphid species. Treatment with EOs also induced generation of reactive oxygen species (ROS) within aphid tissues. The highest levels of superoxide anion and hydrogen peroxide were noted after 24 and 48 h of exposure. Moreover, a significant increase in lipid peroxidation was shown in treated aphids, especially between 48 and 72 h after exposure. The increase was more pronounced after treatment with the essential oil of S. chamaecyparissus, which also exhibited higher aphicidal activity in toxicity tests. The activities of antioxidant enzymes—superoxide dismutase (SOD) and catalase (CAT)—were significantly elevated in both aphid species in response to the tested EOs. The obtained results suggest that oxidative stress evoked by treatment with the studied EOs may be an important factor determining their toxicity towards aphids. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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14 pages, 3309 KiB  
Article
Selection and Validation of Suitable Reference Genes for RT-qPCR Analysis in the Rare Aquatic Firefly Aquatica leii (Coleoptera: Lampyridae)
by Xinhua Fu and Victor Benno Meyer-Rochow
Insects 2021, 12(4), 359; https://doi.org/10.3390/insects12040359 - 16 Apr 2021
Cited by 6 | Viewed by 3063
Abstract
Aquatica leii Fu and Ballantyne is a species of rare aquatic firefly and endemic in China. It is considered good material to study the molecular mechanism of sexual flash communication systems. To improve conservation and behavioral research strategies, large-scale genetic studies involving gene-expression [...] Read more.
Aquatica leii Fu and Ballantyne is a species of rare aquatic firefly and endemic in China. It is considered good material to study the molecular mechanism of sexual flash communication systems. To improve conservation and behavioral research strategies, large-scale genetic studies involving gene-expression analysis are required and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is the most commonly used method. However, there have been very few reports on appropriate reference genes in any species of firefly. Here, we evaluated eight widely utilized reference genes including 18S, Actin, Reep5, Odc1, Tub, Gapdh, Ef1a and S27Ae for their expression stabilities in A. leii under three different conditions, i.e., life stage, tissue and dsRNA injection. Based on the gene stability ranking calculated by RefFinder, which integrates four algorithms (geNorm, delta Ct method, NormFinder, and BestKeeper), we recommend S27Ae and Reep5 as the most appropriate reference genes for molecular studies in different life stages; Ef1a and Odc1 for different tissues; Tub and Odc1 for RNAi studies. The most appropriate reference genes in all treatments are S27Ae and Tub. The results of this study will help improve accuracy and reliability to normalize RT-qPCR data in A. leii for further molecular analysis. Full article
(This article belongs to the Special Issue Reproductive Behaviour in Insects and other Non-Marine Arthropods)
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14 pages, 2320 KiB  
Review
Identifying Molecular-Based Trophic Interactions as a Resource for Advanced Integrated Pest Management
by Jason M. Schmidt, Angelita Acebes-Doria, Brett Blaauw, Arash Kheirodin, Swikriti Pandey, Kylie Lennon, Amos D. Kaldor, Pedro F. S. Toledo and Erin E. Grabarczyk
Insects 2021, 12(4), 358; https://doi.org/10.3390/insects12040358 - 16 Apr 2021
Cited by 12 | Viewed by 4258
Abstract
Biodiversity is an essential attribute of sustainable agroecosystems. Diverse arthropod communities deliver multiple ecosystem services, such as biological control, which are the core of integrated pest management programs. The molecular analysis of arthropod diets has emerged as a new tool to monitor and [...] Read more.
Biodiversity is an essential attribute of sustainable agroecosystems. Diverse arthropod communities deliver multiple ecosystem services, such as biological control, which are the core of integrated pest management programs. The molecular analysis of arthropod diets has emerged as a new tool to monitor and help predict the outcomes of management on the functioning of arthropod communities. Here, we briefly review the recent molecular analysis of predators and parasitoids in agricultural environments. We focus on the developments of molecular gut content analysis (MGCA) implemented to unravel the function of community members, and their roles in biological control. We examine the agricultural systems in which this tool has been applied, and at what ecological scales. Additionally, we review the use of MGCA to uncover vertebrate roles in pest management, which commonly receives less attention. Applying MGCA to understand agricultural food webs is likely to provide an indicator of how management strategies either improve food web properties (i.e., enhanced biological control), or adversely impact them. Full article
(This article belongs to the Collection Improving IPM of Specialty Crop Pests and Global Food Security)
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11 pages, 1631 KiB  
Article
The Effects of Exposure to Flupyradifurone on Survival, Development, and Foraging Activity of Honey Bees (Apis mellifera L.) under Field Conditions
by Yi Guo, Qing-Yun Diao, Ping-Li Dai, Qiang Wang, Chun-Sheng Hou, Yong-Jun Liu, Li Zhang, Qi-Hua Luo, Yan-Yan Wu and Jing Gao
Insects 2021, 12(4), 357; https://doi.org/10.3390/insects12040357 - 16 Apr 2021
Cited by 9 | Viewed by 2632
Abstract
Flupyradifurone (FPF) is a novel systemic nAChR agonist that interferes with signal transduction in the central nervous system of sucking pests. Despite claims that FPF is potentially “bee-safe” by risk assessments, laboratory data have suggested that FPF has multiple sub-lethal effects on individual [...] Read more.
Flupyradifurone (FPF) is a novel systemic nAChR agonist that interferes with signal transduction in the central nervous system of sucking pests. Despite claims that FPF is potentially “bee-safe” by risk assessments, laboratory data have suggested that FPF has multiple sub-lethal effects on individual honey bees. Our study aimed to expand the studies to the effects of field-realistic concentration of FPF. We found a statistically significant decrease in the survival rate of honey bees exposed to FPF, whereas there were no significantly negative effects on larvae development durations nor foraging activity. In addition, we found that the exposed foragers showed significantly higher expression of ApidNT, CYP9Q2, CYP9Q3, and AmInR-2 compared to the CK group (control group), but no alteration in the gene expression was observed in larvae. The exposed newly emerged bees showed significantly higher expression of Defensin and ApidNT. These results indicate that the chronic exposure to the field-realistic concentration of FPF has negligible effects, but more important synergistic and behavioral effects that can affect colony fitness should be explored in the future, considering the wide use of FPF on crops pollinated and visited by honey bees. Full article
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10 pages, 1049 KiB  
Article
UDP-Glycosyltransferases from the UGT344 Family Are Involved in Sulfoxaflor Resistance in Aphis gossypii Glover
by Kangsheng Ma, Qiuling Tang, Pingzhuo Liang, Jianhong Li and Xiwu Gao
Insects 2021, 12(4), 356; https://doi.org/10.3390/insects12040356 - 16 Apr 2021
Cited by 17 | Viewed by 2485
Abstract
UDP-glycosyltransferases (UGTs) are major phase II detoxification enzymes that catalyze the transfer of glycosyl residues from activated nucleotide sugars to acceptor hydrophobic molecules and play very important roles in the biotransformation of various endogenous and exogenous compounds. Our previous studies demonstrated that UGTs [...] Read more.
UDP-glycosyltransferases (UGTs) are major phase II detoxification enzymes that catalyze the transfer of glycosyl residues from activated nucleotide sugars to acceptor hydrophobic molecules and play very important roles in the biotransformation of various endogenous and exogenous compounds. Our previous studies demonstrated that UGTs participated in the detoxification of insecticides in Aphis gossypii. However, the potential roles of UGTs in A. gossypii resistance to sulfoxaflor are still unclear. In this study, two inhibitors of UGT enzymes, sulfinpyrazone and 5-nitrouracil, significantly increased the toxicity of sulfoxaflor to a resistant strain of A. gossypii, whereas there were no synergistic effects in the susceptible strain. Based on the transcriptome sequencing results, the expression levels of 15 UGTs were analyzed by quantitative real-time PCR, and we found that seven UGT genes were highly over-expressed in a sulfoxaflor-resistant strain compared to the susceptible strain, including UGT344B4, UGT344C5, UGT344A11, UGT344A14, and UGT344L2. Further suppressing the expression of UGT344B4, UGT344C5, and UGT344A11 by RNA interference significantly increased the sensitivity of resistant aphids to sulfoxaflor, indicating that the overexpression of UGT genes is potentially associated with sulfoxaflor resistance. These results could provide valuable information for further understanding the mechanisms of insecticide resistance. Full article
(This article belongs to the Section Insect Molecular Biology and Genomics)
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13 pages, 2206 KiB  
Article
Dose–Response Assay for Synthetic Mosquito (Diptera: Culicidae) Attractant Using a High-Throughput Screening System
by Dae-Yun Kim, Theerachart Leepasert, Michael J. Bangs and Theeraphap Chareonviriyaphap
Insects 2021, 12(4), 355; https://doi.org/10.3390/insects12040355 - 16 Apr 2021
Cited by 6 | Viewed by 3281
Abstract
Natural volatile host cues play a critical role for mosquito orientation and locating a blood source for egg production. Similar olfactory activation responses have allowed the use and development of artificial chemical attractants to lure mosquitoes to trapping devices. Using a pre-formulated commercial [...] Read more.
Natural volatile host cues play a critical role for mosquito orientation and locating a blood source for egg production. Similar olfactory activation responses have allowed the use and development of artificial chemical attractants to lure mosquitoes to trapping devices. Using a pre-formulated commercial product mixture of different attractant chemicals, a high-throughput screening system (HITSS) is used to screen varying doses of chemical required to activate behavioral responses. Two strains of Aedes aegypti (L.): permethrin-susceptible (USDA) and -resistant (Pu Teuy) phenotypes and one Culex quinquefasciatus Say. (NIH) laboratory strain were tested. Overall, mosquitoes showed repellency between 1.0 g and to 10.0 g dose of each compound. However, by progressively reducing the dose, Cx. quinquefasciatus showed a greater positive percent attraction (88.9%) at 0.025 g, whereas the USDA and Pu Teuy Ae. aegypti produced optimum attractant activation at 0.005 g (72.6% and 58.9%, respectively) without significant difference within species (p > 0.05). In parallel control assays, Cx. quinquefasciatus was significantly attracted to 1 g of dry ice (carbon dioxide) (76%) more than Ae. aegypti (USDA) (12.2%). The HITSS was originally designed to measure three chemical actions to sublethal concentrations of chemicals by mosquitoes: toxicity and the two primary behavior avoidance responses (contact excitation and spatial repellency). These findings demonstrate that the HITSS assay, with only minor modifications, allows comparison screening of candidate compounds as potential attractants for anemotactic responses under laboratory-controlled conditions. Further investigations will be required to equate measurements obtained from controlled laboratory assays to more varied field conditions for attracting natural mosquito populations. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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12 pages, 1890 KiB  
Article
Discovery of Lebambromyia in Myanmar Cretaceous Amber: Phylogenetic and Biogeographic Implications (Insecta, Diptera, Phoroidea)
by Davide Badano, Qingqing Zhang, Michela Fratini, Laura Maugeri, Inna Bukreeva, Elena Longo, Fabian Wilde, David K. Yeates and Pierfilippo Cerretti
Insects 2021, 12(4), 354; https://doi.org/10.3390/insects12040354 - 16 Apr 2021
Cited by 1 | Viewed by 2189
Abstract
Lebambromyia sacculifera sp. nov. is described from Late Cretaceous amber from Myanmar, integrating traditional observation techniques and X-ray phase contrast microtomography. Lebambromyia sacculifera is the second species of Lebambromyia after L. acrai Grimaldi and Cumming, described from Lebanese amber (Early Cretaceous), and the [...] Read more.
Lebambromyia sacculifera sp. nov. is described from Late Cretaceous amber from Myanmar, integrating traditional observation techniques and X-ray phase contrast microtomography. Lebambromyia sacculifera is the second species of Lebambromyia after L. acrai Grimaldi and Cumming, described from Lebanese amber (Early Cretaceous), and the first record of this taxon from Myanmar amber, considerably extending the temporal and geographic range of this genus. The new specimen bears a previously undetected set of phylogenetically relevant characters such as a postpedicel sacculus and a prominent clypeus, which are shared with Ironomyiidae and Eumuscomorpha. Our cladistic analyses confirmed that Lebambromyia represented a distinct monophyletic lineage related to Platypezidae and Ironomyiidae, though its affinities are strongly influenced by the interpretation and coding of the enigmatic set of features characterizing these fossil flies. Full article
(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)
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15 pages, 2173 KiB  
Article
Remarkable Population Resilience in a North African Endemic Damselfly in the Face of Rapid Agricultural Transformation
by Rassim Khelifa, Hayat Mahdjoub, Affef Baaloudj, Robert A. Cannings and Michael J. Samways
Insects 2021, 12(4), 353; https://doi.org/10.3390/insects12040353 - 15 Apr 2021
Cited by 6 | Viewed by 2085
Abstract
Agriculture can be pervasive in its effect on wild nature, affecting various types of natural habitats, including lotic ecosystems. Here, we assess the extent of agricultural expansion on lotic systems in Northern Africa (Algeria, Tunisia, and Morocco) and document its overlap with the [...] Read more.
Agriculture can be pervasive in its effect on wild nature, affecting various types of natural habitats, including lotic ecosystems. Here, we assess the extent of agricultural expansion on lotic systems in Northern Africa (Algeria, Tunisia, and Morocco) and document its overlap with the distribution of an endemic damselfly, Platycnemis subdilatata Selys, using species distribution modeling. We found that agricultural land cover increased by 321% in the region between 1992 and 2005, and, in particular, the main watercourses experienced an increase in agricultural land cover from 21.4% in 1992 to 78.1% in 2005, together with an increase in the intensity of 226% in agricultural practices. We used capture–mark–recapture (CMR) surveys in terrestrial habitats surrounding a stream bordered by grassland and cropland in northeastern Algeria to determine demographic parameters and population size, as well as cropland occupancy. CMR modeling showed that the recapture and survival probabilities had an average of 0.14 (95%CI: 0.14–0.17) and 0.86 (0.85–0.87), respectively. We estimated a relatively large population of P. subdilatata (~1750 individuals) in terrestrial habitats. The occupancy of terrestrial habitats by adults was spatially structured by age. Our data suggest that P. subdilatata has survived agricultural expansion and intensification better than other local odonate species, mainly because it can occupy transformed landscapes, such as croplands and grasslands. Full article
(This article belongs to the Special Issue Odonates in Human Environments)
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18 pages, 4237 KiB  
Article
Friends in All the Green Spaces: Weather Dependent Changes in Urban Mosquito (Diptera: Culicidae) Abundance and Diversity
by Heli Kirik, Viktoria Burtin, Lea Tummeleht and Olavi Kurina
Insects 2021, 12(4), 352; https://doi.org/10.3390/insects12040352 - 15 Apr 2021
Cited by 7 | Viewed by 2606
Abstract
Mosquitoes (Diptera: Culicidae) are universally recognized as troublesome pests and vectors of various pathogens and parasites. Understandably, the species makeup and diversity of individual populations depends on local and broad scale environmental trends, especially on temperature and hydrological variations. Anthropogenic landscapes make for [...] Read more.
Mosquitoes (Diptera: Culicidae) are universally recognized as troublesome pests and vectors of various pathogens and parasites. Understandably, the species makeup and diversity of individual populations depends on local and broad scale environmental trends, especially on temperature and hydrological variations. Anthropogenic landscapes make for unique habitats, but their effect on insects likely varies across climatic regions. The aim of this study was to investigate the diversity and seasonal patterns of urban mosquitoes in the boreal region. Specimens were collected with an insect net from May to September during three years and determined to species or species group level. Weather information was added to each data point and results analyzed using multivariate regression models. Fieldwork yielded 1890 mosquitoes from four genera. Both abundance and the effective number of species (ENS) significantly decreased during the study period. The number of collected mosquitoes had a negative correlation with wind speed and temperature, latter of which exhibited a negative association with humidity. Species succession followed predictable patterns, but with some variation between years. Still, Culex pipiens/Culex torrentium were the most abundant throughout the study. Importantly, all dominant species were known disease vectors. Our work showed that higher temperatures could result in fewer mosquitoes in boreal towns. Full article
(This article belongs to the Special Issue Diptera Diversity in Space and Time)
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11 pages, 1353 KiB  
Article
The microRNA miR-14 Regulates Egg-Laying by Targeting EcR in Honeybees (Apis mellifera)
by Xiao Chen and Jinluan Fu
Insects 2021, 12(4), 351; https://doi.org/10.3390/insects12040351 - 14 Apr 2021
Cited by 10 | Viewed by 1965
Abstract
Honeybees (Apis mellifera) are important pollinators and are commonly used for honey production. The oviposition behavior in honeybees is complex and errors in oviposition could affect the development of the bee colony. Recent studies reported that RNA–RNA cross-talk played a critical [...] Read more.
Honeybees (Apis mellifera) are important pollinators and are commonly used for honey production. The oviposition behavior in honeybees is complex and errors in oviposition could affect the development of the bee colony. Recent studies reported that RNA–RNA cross-talk played a critical role in several biological processes, including reproduction. Ecdysone receptor (EcR) and miR-14 were previously reported to play important roles in egg-laying. Moreover, EcR was predicted to be the target gene of miR-14 and may form miR-14-EcR cross-talk. In this study, knocking down and overexpression of miR-14 and EcR in queen model were implemented. The effect of RNA expression of miR-14 and EcR on the number of eggs laid by honeybee queens were analyzed. Further, luciferase assay was used to confirm the target relation between miR-14 and 3′UTR of EcR. The results showed that the expression of miR-14 and EcR was associated with the number of eggs laid by queens. In specific, inhibition of miR-14 expression enhanced the number of eggs laid, while overexpression of EcR enhanced the number of eggs laid. Lastly, we determined that miR-14 directly targets the mRNA of EcR. These findings suggest that the cross-talk of miR-14-EcR plays an important role in the number of eggs laid by honeybee queens. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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12 pages, 1643 KiB  
Article
Sexual Dimorphism and Morphological Modularity in Acanthoscelides obtectus (Say, 1831) (Coleoptera: Chrysomelidae): A Geometric Morphometric Approach
by Sanja Budečević, Uroš Savković, Mirko Đorđević, Lea Vlajnić and Biljana Stojković
Insects 2021, 12(4), 350; https://doi.org/10.3390/insects12040350 - 14 Apr 2021
Cited by 3 | Viewed by 3094
Abstract
Sexual dimorphism and specific patterns of development contribute in a great manner to the direction and degree of the sexual differences in body size and shape in many insects. Using a landmark-based geometric morpohometrics approach, we investigated sex-specific morphological size and shape variation [...] Read more.
Sexual dimorphism and specific patterns of development contribute in a great manner to the direction and degree of the sexual differences in body size and shape in many insects. Using a landmark-based geometric morpohometrics approach, we investigated sex-specific morphological size and shape variation in the seed beetle, Acanthoscelides obtectus. We also tested the functional hypothesis of the two morphological modules—thorax and abdomen in both sexes. Female-biased sexual dimorphism in size was shown, while differences in shape were reflected in the wider thorax and abdomen and shorter abdomen in females in comparison to males. The functional hypothesis of a two-module body was confirmed only in females before correction for size, and in both sexes after the allometry correction. Our results indicate that reproductive function has the central role in forming the patterns of modularity. We hypothesize that high morphological integration of the abdomen in females results from intense stabilizing selection, while the more relaxed integration in males is driven by the higher intensity of sexual selection. Full article
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28 pages, 5274 KiB  
Article
Influence of Vineyard Inter-Row Groundcover Vegetation Management on Arthropod Assemblages in the Vineyards of North-Eastern Italy
by Giulia Zanettin, Angela Bullo, Alberto Pozzebon, Giovanni Burgio and Carlo Duso
Insects 2021, 12(4), 349; https://doi.org/10.3390/insects12040349 - 14 Apr 2021
Cited by 10 | Viewed by 2721
Abstract
In this study, the effects of habitat management practices on both pests and beneficial arthropods were evaluated in vineyards of North-eastern Italy through different field experiments: (1) mowing of inter-row spontaneous grasses in conventional and organic vineyards, (2) different timing of mowing of [...] Read more.
In this study, the effects of habitat management practices on both pests and beneficial arthropods were evaluated in vineyards of North-eastern Italy through different field experiments: (1) mowing of inter-row spontaneous grasses in conventional and organic vineyards, (2) different timing of mowing of a green manure mixture, and (3) comparing different green manure mixtures. The first experiment followed a split-plot design, while randomized block design was used in the second and third experiment. In each experiment arthropods were sampled using different methods: leaf sampling, beating and sweep net sampling. Non-mowed spontaneous grasses in inter-rows of vineyards favored the abundance of natural enemies (e.g., predatory mites, parasitic wasps and spiders), and sometimes grapevine leafhoppers. Many arthropod species were recorded in higher numbers in organic vineyards. Late mowing of green manure favored beneficial arthropods (e.g., spiders and parasitic wasps), while it did not influence herbivore density. Groundcover management practices, aimed at increasing plant biodiversity in vineyards, could be a useful tool to enhance beneficial arthropod abundance, although the adoption of this practice should be carefully evaluated when pests occur. Semi-natural areas can contribute to create a more pest-stable agro-ecosystem and should be integrated with appropriate ecological infrastructures surrounding vineyards. Full article
(This article belongs to the Special Issue Improving Functional Biodiversity in Vineyards)
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14 pages, 2489 KiB  
Article
Unique Duplication of trnN in Odontoptilum angulatum (Lepidoptera: Pyrginae) and Phylogeny within Hesperiidae
by Jiaqi Liu, Jintian Xiao, Xiangyu Hao and Xiangqun Yuan
Insects 2021, 12(4), 348; https://doi.org/10.3390/insects12040348 - 14 Apr 2021
Cited by 5 | Viewed by 2196
Abstract
To explore the variation and relationship between gene rearrangement and phylogenetic effectiveness of mitogenomes among lineages of the diversification of the tribe Tagiadini in the subfamily Pyrginae, we sequenced the complete mitogenome of Odontoptilum angulatum. The genome is 15,361 bp with the [...] Read more.
To explore the variation and relationship between gene rearrangement and phylogenetic effectiveness of mitogenomes among lineages of the diversification of the tribe Tagiadini in the subfamily Pyrginae, we sequenced the complete mitogenome of Odontoptilum angulatum. The genome is 15,361 bp with the typical 37 genes, a large AT-rich region and an additional trnN (trnN2), which is completely identical to trnN (sequence similarity: 100%). The gene order differs from the typical Lepidoptera-specific arrangement and is unique to Hesperiidae. The presence of a “pseudo-trnS1” in the non-coding region between trnN1 and trnN2 supports the hypothesis that the presence of an extra trnN can be explained by the tandem duplication-random loss (TDRL) model. Regarding the phylogenetic analyses, we found that the dataset comprising all 37 genes produced the highest node support, as well as a monophyly of Pyrginae, indicating that the inclusion of RNAs improves the phylogenetic signal. Relationships among the subfamilies in Hesperiidae were also in general agreement with the results of previous studies. The monophyly of Tagiadini is strongly supported. Our study provides a new orientation for application of compositional and mutational biases of mitogenomes in phylogenetic analysis of Tagiadini and even all Hesperiidae based on larger taxon sampling in the future. Full article
(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)
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12 pages, 775 KiB  
Article
Potential Global Distribution of Daktulosphaira vitifoliae under Climate Change Based on MaxEnt
by Wei Ji, Gary Gao and Jiufeng Wei
Insects 2021, 12(4), 347; https://doi.org/10.3390/insects12040347 - 13 Apr 2021
Cited by 20 | Viewed by 3084
Abstract
Grape phylloxera, Daktulosphaira vitifoliae, is a small, invasive, sap-sucking pest that is widely present in most viticulture regions all over the world. It is originally from North America and feeds on grapevine roots and leaves. In the current study, the potential distribution [...] Read more.
Grape phylloxera, Daktulosphaira vitifoliae, is a small, invasive, sap-sucking pest that is widely present in most viticulture regions all over the world. It is originally from North America and feeds on grapevine roots and leaves. In the current study, the potential distribution area of the leaf-feeding population was investigated with MaxEnt based on population occurrence data under different environmental variables. Results suggested that under current climatic conditions, Europe, East and North China, Japan, the Eastern USA, Uruguay, and the Southeast of South America are highly suitable areas for the occurrence of phylloxera leaf populations. The results showed that isothermality and precipitation of coldest quarter were major factors which contribute more than 60% of the model under current climate conditions. Our results provide important information for governmental decision makers and famers to develop control and management strategies against D. vitifoliae, and can also be used as a reference for studies on other invasive pest. Full article
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48 pages, 2642 KiB  
Review
The Insect Pest Control Laboratory of the Joint FAO/IAEA Programme: Ten Years (2010–2020) of Research and Development, Achievements and Challenges in Support of the Sterile Insect Technique
by Marc J. B. Vreysen, Adly M. M. Abd-Alla, Kostas Bourtzis, Jeremy Bouyer, Carlos Caceres, Chantel de Beer, Danilo Oliveira Carvalho, Hamidou Maiga, Wadaka Mamai, Katerina Nikolouli, Hanano Yamada and Rui Pereira
Insects 2021, 12(4), 346; https://doi.org/10.3390/insects12040346 - 13 Apr 2021
Cited by 26 | Viewed by 7002
Abstract
The Joint FAO/IAEA Centre (formerly called Division) of Nuclear Techniques in Food and Agriculture was established in 1964 and its accompanying laboratories in 1961. One of its subprograms deals with insect pest control, and has the mandate to develop and implement the sterile [...] Read more.
The Joint FAO/IAEA Centre (formerly called Division) of Nuclear Techniques in Food and Agriculture was established in 1964 and its accompanying laboratories in 1961. One of its subprograms deals with insect pest control, and has the mandate to develop and implement the sterile insect technique (SIT) for selected key insect pests, with the goal of reducing the use of insecticides, reducing animal and crop losses, protecting the environment, facilitating international trade in agricultural commodities and improving human health. Since its inception, the Insect Pest Control Laboratory (IPCL) (formerly named Entomology Unit) has been implementing research in relation to the development of the SIT package for insect pests of crops, livestock and human health. This paper provides a review of research carried out between 2010 and 2020 at the IPCL. Research on plant pests has focused on the development of genetic sexing strains, characterizing and assessing the performance of these strains (e.g., Ceratitis capitata), elucidation of the taxonomic status of several members of the Bactrocera dorsalis and Anastrepha fraterculus complexes, the use of microbiota as probiotics, genomics, supplements to improve the performance of the reared insects, and the development of the SIT package for fruit fly species such as Bactrocera oleae and Drosophila suzukii. Research on livestock pests has focused on colony maintenance and establishment, tsetse symbionts and pathogens, sex separation, morphology, sterile male quality, radiation biology, mating behavior and transportation and release systems. Research with human disease vectors has focused on the development of genetic sexing strains (Anopheles arabiensis, Aedes aegypti and Aedes albopictus), the development of a more cost-effective larvae and adult rearing system, assessing various aspects of radiation biology, characterizing symbionts and pathogens, studying mating behavior and the development of quality control procedures, and handling and release methods. During the review period, 13 coordinated research projects (CRPs) were completed and six are still being implemented. At the end of each CRP, the results were published in a special issue of a peer-reviewed journal. The review concludes with an overview of future challenges, such as the need to adhere to a phased conditional approach for the implementation of operational SIT programs, the need to make the SIT more cost effective, to respond with demand driven research to solve the problems faced by the operational SIT programs and the use of the SIT to address a multitude of exotic species that are being introduced, due to globalization, and established in areas where they could not survive before, due to climate change. Full article
(This article belongs to the Special Issue Sterile Insect Technique (SIT) and Its Applications)
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16 pages, 836 KiB  
Article
A Minor Role of Host Fruit on the Parasitic Performance of Aganaspis daci (Hymenoptera: Figitidae) on Medfly Larvae
by Luis de Pedro, Ahlem Harbi, José Tormos, Beatriz Sabater-Muñoz and Francisco Beitia
Insects 2021, 12(4), 345; https://doi.org/10.3390/insects12040345 - 13 Apr 2021
Cited by 4 | Viewed by 2371
Abstract
Host fruit is known to strongly affect the performance of both fruit pests and their potential natural enemies. This is particularly important in the control of tephritid fruit flies, whose larvae develop inside the fruit and thus create a set of foraging problems [...] Read more.
Host fruit is known to strongly affect the performance of both fruit pests and their potential natural enemies. This is particularly important in the control of tephritid fruit flies, whose larvae develop inside the fruit and thus create a set of foraging problems for parasitoids. In the present study, we assessed the response of female Aganaspis daci (Weld) (Hymenoptera: Figitidae), one of the most promising parasitoids for tephritid biocontrol in the Mediterranean Basin, to different potential host fruit species. We measured the olfactory response to medfly-infested and uninfested fruits, and several biological parameters of A. daci when different infested fruits were offered under both laboratory and greenhouse conditions. Our results showed that this parasitoid was significantly more attracted to apples and uninfested fruit. Moreover, parasitic activity was similar among the tested fruits under both conditions, showing very high values in the laboratory and a much poorer performance when conditions were variable. This suggests that A. daci may be a good candidate to be included in mass releases against the medfly regardless of the affected crop, but only when climate conditions are not expected to hinder its normal activity. Full article
(This article belongs to the Special Issue Sustainable Management Methods for Orchard Insect Pests)
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11 pages, 779 KiB  
Article
The Fate of Deroceras reticulatum Following Metaldehyde Poisoning
by Amy Campbell, Neil Audsley and Gordon Port
Insects 2021, 12(4), 344; https://doi.org/10.3390/insects12040344 - 13 Apr 2021
Cited by 8 | Viewed by 2617
Abstract
The concentration of a pesticide used in agriculture not only has implications for effectiveness of pest control but may also have significant wider environmental consequences. This research explores the acceptability of metaldehyde slug pellets at different concentrations by Deroceras reticulatum (Müller, 1774) (Agriolimacidae), [...] Read more.
The concentration of a pesticide used in agriculture not only has implications for effectiveness of pest control but may also have significant wider environmental consequences. This research explores the acceptability of metaldehyde slug pellets at different concentrations by Deroceras reticulatum (Müller, 1774) (Agriolimacidae), and the changes in the health status of the slug when allowed to recover. The highest metaldehyde concentration (5%) yielded the highest slug mortality; however, it also produced the highest proportion of unpoisoned slugs, suggesting the highest level of pellet rejection. Pellets with 1% metaldehyde were as effective as 3% pellets in paralysing a significant proportion of the population after initial pellet exposure; however, more slugs were able to recover from metaldehyde poisoning at 1% metaldehyde compared with 3%. There was no statistically significant difference between the mortality rate of slugs regardless of metaldehyde concentration, suggesting that a lower concentration of metaldehyde may be as effective as a higher concentration. Full article
(This article belongs to the Special Issue Biology and Management of Slug and Snail Pests)
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13 pages, 1521 KiB  
Article
Mating Disruption of Pseudococcus calceolariae (Maskell) (Hemiptera, Pseudococcidae) in Fruit Crops
by Carolina Ballesteros, Alda Romero, María Colomba Castro, Sofía Miranda, Jan Bergmann and Tania Zaviezo
Insects 2021, 12(4), 343; https://doi.org/10.3390/insects12040343 - 13 Apr 2021
Cited by 6 | Viewed by 2845
Abstract
Pseudococcus calceolariae, the citrophilous mealybug, is a species of economic importance. Mating disruption (MD) is a potential control tool. During 2017–2020, trials were conducted to evaluate the potential of P. calceolariae MD in an apple and a tangerine orchard. Two pheromone doses, [...] Read more.
Pseudococcus calceolariae, the citrophilous mealybug, is a species of economic importance. Mating disruption (MD) is a potential control tool. During 2017–2020, trials were conducted to evaluate the potential of P. calceolariae MD in an apple and a tangerine orchard. Two pheromone doses, 6.32 g/ha (2017–2018) and 9.45 g/ha (2019–2020), were tested. The intermediate season (2018–2019) was evaluated without pheromone renewal to study the persistence of the pheromone effect. Male captures in pheromone traps, mealybug population/plant, percentage of infested fruit at harvest and mating disruption index (MDI) were recorded regularly. In both orchards, in the first season, male captures were significantly lower in MD plots compared to control plots, with an MDI > 94% in the first month after pheromone deployment. During the second season, significantly lower male captures in MD plots were still observed, with an average MDI of 80%. At the third season, male captures were again significant lower in MD than control plots shortly after pheromone applications. In both orchards, population by visual inspection and infested fruits were very low, without differences between MD and control plots. These results show the potential use of mating disruption for the control of P. calceolariae. Full article
(This article belongs to the Special Issue From Insect Pheromones to Mating Disruption: Theory and Practice)
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16 pages, 7296 KiB  
Article
Automatic Pest Counting from Pheromone Trap Images Using Deep Learning Object Detectors for Matsucoccus thunbergianae Monitoring
by Suk-Ju Hong, Il Nam, Sang-Yeon Kim, Eungchan Kim, Chang-Hyup Lee, Sebeom Ahn, Il-Kwon Park and Ghiseok Kim
Insects 2021, 12(4), 342; https://doi.org/10.3390/insects12040342 - 12 Apr 2021
Cited by 35 | Viewed by 4311
Abstract
The black pine bast scale, M. thunbergianae, is a major insect pest of black pine and causes serious environmental and economic losses in forests. Therefore, it is essential to monitor the occurrence and population of M. thunbergianae, and a monitoring method [...] Read more.
The black pine bast scale, M. thunbergianae, is a major insect pest of black pine and causes serious environmental and economic losses in forests. Therefore, it is essential to monitor the occurrence and population of M. thunbergianae, and a monitoring method using a pheromone trap is commonly employed. Because the counting of insects performed by humans in these pheromone traps is labor intensive and time consuming, this study proposes automated deep learning counting algorithms using pheromone trap images. The pheromone traps collected in the field were photographed in the laboratory, and the images were used for training, validation, and testing of the detection models. In addition, the image cropping method was applied for the successful detection of small objects in the image, considering the small size of M. thunbergianae in trap images. The detection and counting performance were evaluated and compared for a total of 16 models under eight model conditions and two cropping conditions, and a counting accuracy of 95% or more was shown in most models. This result shows that the artificial intelligence-based pest counting method proposed in this study is suitable for constant and accurate monitoring of insect pests. Full article
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